The human eye in its simplest terms functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of the lens onto the retina. When age or disease cause the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is surgical removal of the lens and replacement of the lens function by an intraocular lens (“IOL”). The natural lens or crystalline lens of the eye can be described as having a central part, i.e., the nucleus, surrounded by the cortex, which is in turn surrounded by the lens capsule having anterior and posterior portions.
In the United States, and in most parts of the world the majority of cataractous lenses are removed by a surgical technique called phacoemulsification. During this procedure, a thin phacoemulsification cutting tip is inserted into the diseased lens and vibrated ultrasonically. A typical ultrasonic surgical instrument suitable for ophthalmic procedures consists of an ultrasonic handpiece, an attached cutting tip, an irrigating sleeve and a control console. The handpiece assembly is attached to the control console by an electric cable and flexible tubing. Through the electric cable, the console varies the power level transmitted by the handpiece to the attached cutting tip and the flexible tubing supplies irrigation fluid to and draws fluid and lens material from the eye through the handpiece assembly.
The “phaco” probe is an ultrasonic handpiece with a hollow metal tip. The tip of the phaco probe vibrates at an ultrasonic frequency to sculpt and emulsify the nucleus while a pump aspirates particles of the cataract through the tip. Typically the tip is made of titanium or steel. The tip vibrates at an ultrasonic frequency of about 40,000 Hz. This causes the lens material to be emulsified, such as is described in U.S. Pat. No. 6,319,220 to Byisma, herein incorporated by reference in its entirety. The aspiration line connected to the handpiece provides aspiration or “flow” that draws the fluid and lens particles into the tip via the pump (e.g. a peristaltic pump, venturi, vacuum pump, etc., or combinations thereof), and overcomes the repulsive force to some extent of the oscillation energy.
After phacoemulsification of the nucleus, but prior to the insertion of a new lens, it is necessary to remove the cortex. Cortex removal is typically accomplished with strictly mechanical means, such as through suction. However, such suction can, and occasionally will, damage the delicate tissues (i.e. capsule and iris) found in the ocular cavity. Contemporaneously, an irrigation instrument is necessary to replace fluid that is extracted during the suction process. Specifically, the fluid pressure of the eye must be maintained during the aspiration procedure or the eye structure will collapse, leading to severe complications. The current art provides a combined aspirator/irrigator tool that incorporates a metal tube closed and rounded at one end but with a side port/hole through which the cortex is aspirated. A second, larger tube/cylinder covers this aspirating instrument. The larger, enveloping instrument is a sleeve that allows for the introduction of a solution into the eye so as to balance the pressure lost caused by aspiration. Thus the procedure includes an irrigation step and an aspiration step. Furthermore, this procedure can be done bi-manually with a properly designed arrangement of instruments.
What is needed in the art is a method and apparatus for the assisted removal of the cortex, capsule polishing and destruction and removal of other intraocular structures, but which reduces the chance of lasting damage to the eye and allows for quicker removal of the cortex.
Furthermore, polishing the capsule (either the anterior capsule or the posterior capsule) is necessary to remove any remaining epithelial cells so as to prevent the generation of a secondary cataract. The capsule is polished to remove the strata (or very fine cortex or layer of epithelial cells) that remain attached to the capsule. The polishing is different from cortex removal since it is directed to removal of a layer of epithelial cells that remain firmly and solidly attached to the posterior surface of the anterior capsule and the anterior surface of the posterior capsule. Specifically, the posterior surface of the remaining anterior capsule and the anterior surface of the posterior capsule need to be polished to effectuate a completely successful procedure. A successful operation requires that the capsule surface be clear of cells and cortex. If the capsule is not completely cleaned and polished of cells, complications will develop.
The procedures described in the art are suitable for the removal of cataracts. However, the procedures described in the prior art carry risks of severe complications such as the risk of infection and damage to the delicate tissues of the eye. In severe cases, the apparatus and methods currently employed, when used improperly or when the tissues and organs of the eye are already weakened, will result in the loss of vision or the eye. Therefore, what is needed is a method and apparatus that allow for the removal of the elements of the cataractous material in a safe and consistent manner.
Additionally, what is needed is an instrument and method directed to the polishing of the capsule that reduces the potential damage to the capsule and the greater optical organ. Furthermore, what is needed is an instrument and method that lower the risk of complications throughout the surgical procedure.